Tubular chair construction



May 19, 1953 B. F. HARBER TUBULAR CHAIR CONSTRUCTION Filed March 24, 1950 Patented May 19, 1953 fiTATzES WA'TENT OFFICE mum TUBULA QHIQQIRYCQNSTRUCTIONV 'Bieivr Fow er flanker, fort M io, Genes s t Am iqa onmarph 24, 1950, S r l o- 151 625 Y 9611mm. 1 vThis inventionrelates to improvements inehah' eonstructio s and moreparticuiarly to improver merits in collapsible tubular chairs.

Qne of the principal objects er the invention is to provide a chairconstruction affording in"- creased strength while permitting lighter and cheaper construction.

Another important glgject is to provide-a chair construction having "an improved eellapsing action wherein the parts are accurately gamed antitan trolled during relatiye movernent'ankg will mm uneljer simple and convenient manipulation tetween com aactly folded and extende positions.

"In this connection it is's ai-ncztl'le-r rmeimmmeet of the invention to provide a chair action wherein he eight. o a..,nr O w l ac o e e t their to and hold it an extended hesiticnte provide the important and highly desirable safety feature- 0? eli inat ng c air te -l pse ev n hj s the chair 1s only partially extended at the time it eceives a per bns w sht Another object is to provide a collapsing aetich wherein the parts automatically led; against accidental displacement at the firl'ly iolied as wen as extended position.

A further objept is to provide for in a chair the class described, adjustment to different pesttions of recline without in any way disturbing the collapsing action. I v

Still another object is to provide a 'eha-ir 0i attractive appearance and comfortable to 115c.

@1 2 f t e primipa nat s f e en w resides in p'ivotaily' connecting front and rear leg and seat frames to fe-rm an A sh'a-pe with the pivot connections "of the leg framesjforming the ape Qi t e and e s a frame i rm the we bar r the A ith i s pivot connection w th the rear eav e mt uti gqa .fslit n' :Pi lig ine sub tant a ly 9 t in lin 'Q the rear le trams, whereby 1mm; o t e their actin flow thmygh the A ac 's t9 spr ad the les and thereby move th .Slisl' s pir upwa dly to auto a i al y extend t e shah:

W th rega'rQ to the'cella ls ng action i a a u 01 he invention. o pi ot the beak f m to the seat frame on the same'sliqing pivot connecting the seat and rear leg frame, and to pivot the arms to the pivots of the leg frames and to h a k rame mpo tan eat e reside in slotting he inwa d end at the s r ceive the pivot ins 91 t e less-permittin reclining of the shair bra/cl; am 1f ermine a warsly extending s n-re et!- as-mtshss opening w the slots far the reten ion of the back in difierem pesitisms Muslim, the;

Vision iof novel wres -around reimfo im m lload'rsnpponting structural guide m mbers mewed in the item le frame, serving at the sam time as a means tor uiding the slidin hiwt hi the seat and rear leg tram-1:21am as stru tu al mm:

b rs t9 rei for e the lead-terrains tear leg rame:

21h thissonnes en the u des are arrencircle the f ar le flame thma g out hee area sf b ndin st esses, tam-ti ing th use at li hter habits in his ad supw ir f ame ant ansfe ring th load at p watslly nt t the rea through 'p -n erating i guide sl ts in he sunpert ng games and ha ing atrpss sec am-l flim n iensu fieicn as o ttansi r the load in shear, pe mit ing a w um @i metal n the guides,

Another feature o the nven ion resides .m, he ormat on of gu de slot to pr id'e an e'ffiet tive automatic lock with the pin means when the chair is swung to the hilly extended and themed positi ns Another eature oi the invention resi es in th navel onst uct q l oi th r ar leg 'ame' 9 retwice the loa -suppgrting span .a' 'si load s e ses Set up 'ui kl'e'r the Wbighb 0i a perso and to a same time afiord ncreasefi str stural treng h in the frames.

These and pth objects anti r s ues w ll hecome apparent with reier nc to he acc mp ny in drawings. in which metre 11 is a nelispestive I View .01 tubular thei .const imt on in am rs ame with my n ention Fig ulre 2 is a si e eleya ional v w 9t th sh ir in the fully menses pos ti n,

, Fig-ti e 3 is a side e vatimjla vi w shbw h solid lines the chair partially collapsed and i1; dott d l n the cha r in its .ful y col a se position v I Figure is an emerged ir smenta y pa tasw tlonal deta l o the .cbnn ttion between s at back and rear eg frame and sh wing the apt e1 wrap-around guide member in end elemfifin figure 5 is an nlarged e tical sep isnal deta of theplvot co nect b o thelem rame and arm- With meme; no the drawings, it will he seen that the chair o, f a ylnr gity f Ill-Wi ly scamme M-sbaped Wbklh? am ft: min; bar-4k teams L stat 2, le 3 and ea trams A.

-- API3 eve oi the mat mi mt legs 3 ans especti ely are pi a a zly e es-w se to each other and to the angle arms 5 by the pivot pins or rivets 6 which engage in the slots 1 in the flanges of the arms at their forward ends in a manner to provide for different positions of recline. The angle members forming the arms 5 are formed with horizontal flange extension portions 8 rolled under to provide a curved forward edge, giving an attractive appearance and also increasing the strength of the section and providing a guard for preventing catching of the fingers between the tubes and the arms in opening and closing the chair.

Pivoted to the front leg frame below the arms 5 adjacent its bight 9 is the seat frame 2, and the free ends of the seat and back frames are pivotally connected remote from the front leg frame, as shown particularly in Figure 4.

The connection between the back and seat frames comprises the bar I spanning between and terminating within the extremities of the back frame I and intersecting the seat frame 2.

It will be seen that with the chair frame and arms pivotally connected as described the chair can be swung between the positions of Figures 2 and 3. It is in the control of this collapsing action that the present invention has particular merit in providing for controlled efficient and smooth chair movement, while at the same time providing increased strength and rigidity in the highly stressed load-carrying rear leg frame.

According to the invention, provided on the rear leg frame 4 at opposite sides of the chair are the wrap-around guide members I I, shown particularly in Figures 1 and 4. These guide members are provided with a U-shaped sleevelike portion I2 which, as shown in Figure 4, encircles the tube of the frame 4.

The sleeve portions of the guides are shown as formed with inturned lips I3 adding to the strength of the section and providing a block for the removal of the guide members while permitting them to be sprung around the frame tubing. v

Extending upwardly from the sleeve portions l2 in a substantially vertical plane are the wings I4 which taper towards the floor and which are formed with slots I5 having notches IS in their upper end and inclining inwardly towards the rear leg frame adjacent their lower end to bring their lower ends into alignment with the notches I6 on a line parallel with the rear leg frame.

The guide members II are anchored to the rear leg frame by the screws IT or other suitable means, and in surrounding or encircling the tube of the rear leg frame greatly increase the rigidity of the frame and resistance to bending at the critical section where the load of the seat and back frames are transferred thereto and where maximum bending stresses occur under load.

The transfer of the load supported by the seat and back frames is accomplished through the screws I9 threaded through the back frame I and into the ends of the cross tube l0, serving as projecting pivot means operating in the slots I5 of the guide members II.

The outer face of the web of the wings I4 is preferably countersunk at to increase the bearing surface between the screws l9 and their heads 2| and the slotted wings I4.

The rear leg frame 4 has the lower portion forming the floor-engaging portion and including the bight of the frame bent angularly at 22 inwardly into a substantially upright position with the chair extended, as shown in Figure 2.

The portion of the frame 4 forming the bight of the frame is preferably bent up at 23 intermediate the width of the frame to provide separate ground-engaging extremities 24.

The construction of the rear leg frame and the mounting of the brackets in the form of the guide members II thereon is an important concept of the present invention. It will be seen that the rear leg frame comprises a load-supporting element fixed at the endsiwith the chair extended, and the weight of a person sitting on the chair supported by the seat frame 2 and covering 25 carried thereby and back frame I and covering 26 carried thereby is transferred through the screws I9 to the rear leg frame intermediate the supported ends. Thus the bending stresses imparted to this latter frame are determined by the weight of the person and length of the unsupported rear leg section.

Normally, to withstand the high bending stresses a frame of heavy tubing would be required. Under the present invention however by employing the guide members II rigidly secured to the leg frame along the section of maximum bending stress these guide members serve the function of increasing the resistance of the sections to bending, permitting lighter tubing to be employed in the load-carrying. rear leg frame than would be required if this frame had to bear the load without strengthening in its intermediate sections.

The result is a chair of lighter and cheaper construction is provided while an improved collapsing action is afforded, as hereinafter explained.

Additionally to the use of the guide members I I, forming'the dual function of guiding the collapsing and opening movements of the chair and reinforcing the intermediate rear leg sections for bending, the deforming of the rear .leg frame at 22 still further decreases the stresses in the rear leg frame and permits lighter tube construction.

This reduction in stress occurs because the.

unsupported span under bending stresses between the ends of the rear leg frame is decreased, and further, the actual deformation of this frame adds to the frame rigidity and strength as is well understood.

With the cross bar l0 seating within the tubing of the back frame I the back frame is maintained in correctly spaced relation under loading. This bar I0 is of a cross section to withstand bending under load, and by having it ter-. minate within the back frame the pivot projec-,

tion means in the form of the screws l9 can be of reduced cross section as they are substan tially entirely under shear in transferring the load from the seat and back frames to the .rear leg frame through the guide members II.

These screws l9 are co-axial with the cross bar II) which forms the pivotal connection between the seat and back frames, and in affording reduced cross section from the tubing I0 permits a reduction in the amount of metal required in the web of the wings I4 of the guide members, adding further to the economy and lightness of the chair.

' Collapsing action Referring now particularly to Figure 2, it will be seen that the seat, front and rear leg frames back) and rear leg frame forming the cross bar of the A being the sliding pivot.

Under loading of the chair it: will be seen that road saith-e considered as acting downwardiv through-tire apex of the a to therefore spread the leg frames as the leg frames spread the seat frame forming thecrossbar of the A wilt be urged upwardly to accommodate theleg spread so" that the pivot screwsbe will ride upwardly under load-"ing in the slots- 15 and witl move into the notches Hi. i a i This is an extremely important safety feature for; contrary to conventional chair constructions which collapse under load unless fully extended and locked, the present chair is moved or urged to a fully extended position Joy-loading andin the event it is only partially extended at the time of leading will astonratioany move to the fully extended position with the pivot projecting means 19 firmly seated thenot'ches Hi;

In the collapsing action the chair operates much in the manner of an umbrella with the movfiint of the screws I9 in the slots l5 go erm ing the movement of all pivotal parts. H v

To m ve the chair to the collapsed position," as shown in Figure 3,- the back ano'seat frames are grasped and the chair is lifted clear of the floor as these frames are swung together. Any tendency to lift the chair will r'iidve the screws. 19' which connect or tie the back and seat to the rear legs out of the notches l t, and the simple closing together of the back and seat frames forces the screws to travel along their predetermined linear path formed by the slots and all parts move in controlled and co-ordinated movement to to the finalized position shown in dotted line,

eliminating any uncontrolled frame swinging which might occasion damage to nearby furniture or inconvenience in handling.

, As the chair slides to the fully collapsed position, due to the incline of the slots [5, the pivot screws I9 move inwardly towards the rear leg frame to hold the frames of the chair in collapsed position against accidental opening movement until the back and seat frames are grasped and pulled outwardly as pull is applied to lift the chair in an upward direction.

In the collapsing action it will be noted that the arms 5 are somewhat inclined rearwardly and the notches 21 and 28 formed in the upper longitudinal edges of the slots 1 are inclined forwardly and upwardly, permitting and ensuring movement of the arms forwardly without obstruction until pins 6 enter notches 28.

The slots 1 are so formed that with the pivot pins 6 entered in notches 28 the arm and seat pivot spacings are equal as are the spacings of the front and back frames to provide a pivotal parallelogram as shown in Figure 3. This parallelogram can then fold by extending its increasing length along the slots E5 of the leg members i l, Figure 3.

With the chair extended the notches 21 and 28 block rearward movement of the arms with the weight of the arms automatically causing entry of the pins into the notches. Thus the back frame I is adjustable to different positions of recline about the pivot rod Ill forming the sliding seat and back pivot in the slides l l and is locked in adjusted recline position against rearward movement.

While -I have shown the preferred form of my invention, it will be understood that modifications may be made in the precise form of guide member and guiding action without departing from the spirit of the invention wherein guiding of the chair and controlling of the chair movement is 6 accomplished through. the of structural members reinforcing the main load-carrying chair name, permitting lighter overatl chair construcfrom g claim as my invention is:

L- In a; coliapsible tubular chair construction hating pivotally connected back, seat, front and fearless frames with said seat frame pivoted at the rear to the lower end of said back frame, a. pair of guide members" having sleeve portions: enoirciing portions of said rear leg frame inter mediate the top andbottom and at opposite sides or the chair to reinforce said rear Ieg frame in sendingand having wing portions projecting from said sleeves and formed with elongated slots therein,-- pivot means forming an extension of the pivotal connection of said back and seat frames and entered in said slots affording a linear sliding: pivotal control connection tying the pivot of said back andseatframes to said rear leg frame" and eon-straining the pivots of saidback and seat frames to move in guided linear sliding motion along said rear leg frame while permitting free pivotal movement of said back and seat frames, said slots terminating at their upper ends notchesseating said pivot means against movemerit in said slots under load upon said chair being extended.

2. A device as maimed in claim 1 in which the slots in said wing portions of said guide members incline inwardly towards the bottom of said rear leg frame.

3. In a collapsible tubular chair, U-shaped front and rear leg frames pivotally connected at their upper open ends, U -shaped back and seat frames pivotally connected at their open ends, said seat frame being pivoted to said front leg frame, arms pivoted to said back frame and to said leg frames, a pair of wraparound guide members encircling said rear leg frame and strengthening same in bending intermediate the length thereof at opposite sides of the chair and formed with longitudinal substantially linear slots, pivotal projection means extending from said back and seat frames and engaging in the slots in said guide members and forming a sliding pivotal connection tying the pivot of said back and seat frames to said rear leg frame permitting collapsing and extending of the chair while constraining the pivot of said back and seat frame to move in guided linear sliding motion along said rear leg frame while permitting free pivotal movement of said back and seat frames.

4. A device as claimed in claim 3 in which said U-shaped rear leg frame is bent angularly inwardly adjacent the bottom to present a substantially upright floor-engaging lower portion.

5. A device as claimed in claim 3 in which said U-shaped rear leg frame is bent angularly inwardly to define a substantially upright floorengaging bight portion, said bight portion being bent upwardly intermediate the width thereof.

6. A device as claimed in claim 5 in which the pivot connecting said seat and back frames comprises a tubular bar intersecting the seat frame tubing and terminating within the back frame tubing and spacing said back frame, and the pivot means entered in said slots is of a lesser cross section than said bar and comprise screws screws threaded into the ends of said tubular bar and riding in said slots.

'7. A device as claimed in claim 6 in which said guide members are countersunk in their outer surfaces along said slots and said screws having 7, their heads riding on surfaces formed by 0011111361?- sinking. j 1

'8. In" a collapsible tubular chair construction including a front leg frame, an inclined rear leg frame pivotally connected to said. front leg frame, a, seat frame and arms pivotally connected to said front leg frame and a back frame pivotally connected to said arms and seat frame in which means are provided to tie said back and seat frames to said rear leg frame to constrain the point of pivotal connection of said back and seat frames tolinear sliding movement along said rear leg frame while permitting free pivotal movement of said back and seat frames, said means comprising a pair of guide members carried by and reinforcing said rear leg frame, one at each side of the chair, substantially linear slots in said members, and projection means extending coaxially with the pivotal connection of said back and seat frames engaging in said slots and transferring load on said seat to said rear leg frame through said guide members.

9. In a collapsible chair having pivotally connected back,- seat, front and rear leg frames with said seat frame pivoted at the rear to the lower endof said back frame, a pair of guide members encircling portions of said rear leg frame intermediate the top and bottom thereof and at opposite sides of the chair, means forming an extenmovement of the aforesaid connecting means,

along said rear leg frame under loading to maintain said back, seat and rear leg frames against relative movement with the chair in extended position.

BLAIR FOWLER HARBER.

References Cited in the file of this patent UNITED STATES PATENTS Number I Name Date 2,059,940 Freedman Nov. 3, 1936 2,072,075 Travers Feb. 23, 1937 2,243,502 Freedman May 27, 1941 FOREIGN PATENTS Number Country Date 170,111 Great Britain Oct. 13, 1921 .347,96l Italy Apr. 29, 1937 

